Pump bypass liquid control

ABSTRACT

A fluid circulation system having a primary flow circuit for supplying fluid under pressure to an operating unit for performing a desired control function and a secondary flow circuit operative under regulated pressure conditions of said primary flow circuit for effecting a regulated control of the fluid being circulated in said secondary flow circuit. The pressure and rate of flow of fluid in the secondary flow circuit is a function of the pressure and rate of flow of fluid in the primary circuit.

United States Patent [1 1 Ward [451 Aug. 21, 1973 1 PUMP BYPASS LIQUIDCONTROL Elmer F. Ward, 1041 N. LaLimona Dr., Tustin, Calif. 92705 [22]Filed: Apr. 9, 1971 [21] Appl. No.: 132,749

Related US. Application Data [63] Continuation-impart of Ser. No.836,312, June 25,

1969, abandoned.

[76] inventor:

[52] US. Cl. 417/213 [51] Int. Cl. F041) 49/00 [58] Field of Search417/222, 307, 308,

417/213; 91/506; 60/52 S, 52 VS [56] References Cited UNITED STATESPATENTS 7/1960 LeFevre et al 91/506 1/1966 Hann et al. 9/1967 Mowbray417/222 To Opera/mg Uni r From Reservoir 2,102,865 12/1937 Vickers417/308 2,674,092 4/1954 Gardiner 2,892,311 6/1959 Van Gerpen 3,350,88111/1967 D'Amato 3,366,064 1/1968 Stephens et al 60/52 VS PrimaryExaminer-Charles J. Myhre Assistant Examiner-Frank H. McKenzie, .lr.Attorney-E. Wallace Breisch 5 7] ABSTRACT A fluid circulation systemhaving a primary flow circuit for supplying fluid under pressure to anoperating unit for performing a desired control function and a secondaryflow circuit operative under regulated pressure conditions of saidprimary flow circuit for effecting a regulated control of the fluidbeing circulated in said secondary flow circuit. The pressure and rateof flow of fluid in the secondary flow circuit is a function of thepressure and rate of flow of fluid in the primary circuit.

6 Claims, 3 Drawing Figures Ta Filler And Reservoir Patented Aug. 21,1973 2 Sheets-Sheet 2 Wk v.0

QImmm PUMP BYPASS LIQUID CONTROL This application is acontinuation-in-part of my copending application Ser. No. 836,312, filedJune 25, 1969 now abandoned.

BACKGROUND OF INVENTION A method of fluid control of various types ofoperating units is presently accomplished by utilization of fluidcirculation systems wherein high pressure rotary fluid pumps deliverfluid under pressure from a reservoir means to the operating unit andthence return to the reservoir, said operating unit thereby performing adesired control function in accordance with the rate of flow and degreeof pressure of said fluid provided by the fluid pump. In such fluidcirculation systems in addition to the primary control function providedby the circulating fluid under pressure, the fluid is also utilized tooperate ancillary apparatus and serve as a lubricant and coolant forboth the pump and said ancillary apparatus. The pump normally utilizedin such systems is of the type which operates at a constant or variablespeed at a controlled discharge pressure, and with a variable dischargerate.

Cooling and lubrication of a typical pump is accomplished by circulationof the fluid being pumped. At full displacement there is a very generoussupply of coolant flowing through the unit. At zero discharge flow,however, the passage of coolant is limited to leakage flow whichaccumulates in the pump case area. Although this flow is normallyadequate for cooling and lubricating the pump, it is not sufficient toprovide for cooling of ancillaries, such as an electric motor used todrive the pump. In addition, the pressure at which this leakage flow canbe returned to the reservoir is limited to the pressure capability ofthe pump case housing and the pump shaft seal. As a result, this leakageflow (commonly called case flow) is usually restricted to a very lowpressure and, therefore, cannot be combined with the normal system highpressure return flow from the operating unit to the reservoir.

SUMMARY OF THE INVENTION It is an object of the present invention toprovide a new and novel fluid control apparatus of the type supplyingfluid under pressure from a reservoir to an operating unit wherein thecontrol fluid is utilized to control ancillary equipment in thecirculation system. A bypass communication means is provided in a pumpmeans and includes a valve means in a passage whereby the valve meansmay be variably positioned to selectively establish communication from adischarge passage of the pump means to a reservoir in a manner tomaintain circulation of the fluid within the pump and ancillaries whilethe requirements of the operating unit are changed. Relief valve meansmay be provided in association with said bypass communication to furtherprovide a lubricating and cooling means should said bypass communicationbecome ineffective because of excessive pressure therein for any reasonsuch as clogging of filters therein.

Another object of the invention is to provide means for eliminatingbranch circuitry such as filter bypass circuitry when not required.

Still another object of the invention is to provide adequate cooling andlubricating fluid flow to ancillary equipment during periods of lowdischarge rate of flow from the pump.

Other provisions of this invention will become more apparent when takenin conjunction with the following detailed description and accompanyingdrawings wherein:

FIG. 1 is a sectionalized view of the pump shown in a high dischargeopening condition;

FIG. 2 is a sectionalized view of the pumps shown in a low dischargeoperating condition; and

FIG. 3 is a fluid circuit diagram showing the pump and associatedelements as employed to control a fluid operating unit.

DESCRIPTION FIG. 1, FIG. 2

Referring to FIG. 1 and similarly FIG. 2 there is shown a fluid pumpdevice 10 having a casing 12 enclosing a rotary barrel type pump 14 andhereinafter described passageways and valve means comprising the novelfluid control apparatus. The pump 14 is operatively rotated by a shaft16 driven by any suitable motor means 18. The pump 14 includes a barrel20 having a plurality of bores 22 spaced therein in normally parallelrelation with the axis 24 of the barrel 20. Each bore 22 has a piston 26slidably positioned therein and operable with a reciprocating actiontherein responsive to rotation of the barrel 20. The reciprocatingaction of said pistons is effected by having one end of each pistonsecured to a swash plate 28 in a non-rotating yoke 30 which ispositioned at variable angles of inclination with respect to the barrelaxis 24 in a manner to thereby cause the reciprocating movement of thepiston 26 within the bores 22 as the barrel 20 rotates. The length ofstroke of the pistons 26 and consequently the rate of fluid dischargefrom the bores 22 is determined by the degree of the angle at which theyoke 30 is inclined, which in turn is determined by the positioning of ayoke flange 32 between a spring 34 and valve stem 36 as explainedherein. The smaller the degree of angle of inclination of the yoke 30with respect to the axis 24 the greater the degree of rate of dischargeof fluid being pumped by the pistons 26 and similarly as the angle ofinclination of the yoke 30 versus the axis 24 increases the rate ofdischarge of fluid by the pistons 26 is decreased. Movement of the valvestem 36 to the right (explained hereinafter) may cause the axis of yoketo pivot to approach a angle of inclination with the axis 24 of thebarrel 20 (FIG. 2). If a large angle of inclination is maintained, it isof slightly lesser degree than 90 as limited by a suitable stop meansand the spring 34 such that the pumping action of the pump 14 ismaintained to provide a constant circulation of fluid in a mannerdescribed hereinafter.

Included in the pump casing 12 is an intake passage 38 leading from anintake pipe 40 to the face of barrel 20 which is positioned abutting thecasing wall 42 in a manner such that the bores 22 sequentially come intoalignment with the intake passage 38 to receive fluid therein on theintake stroke of the pistons 26. A discharge passage 44 similarly leadsfrom the casing wall 42 at a position where it will come into alignmentwith the bores 22 sequentially to receive fluid under pressuredischarged from the bores 22 on the compression stroke of the pistons 26to thereby supply fluid under pressure to the discharge pipe 46 andthence to an operating unit (labeled as such in FIG. 3).

A spool valve 50 is slidably positioned in a bore 52 within the pumpcasing 12 in a manner such that the right hand extremity or valve stem36 abuts the yoke flange 32 in opposition to biasing forces of spring34. The spring 34 tends to maintain the yoke flange 32 in constantengagement with the valve stem 36 and biased in a leftward direction asviewed in the drawings. The left hand extremity or valve stem 54 of thespool valve 50 is of suitable diameter shown herein as a reduceddiameter for guide means, and slidably extends through a chamber 55 intoa bore 56 which in turn is connected by a passage 58 to the dischargepassage 44. Intermediate the extremities of the spool valve 50 is anannular groove 60 which is in constant communication with a bypasspassage 62 connected to the discharge passage 44. When spool valve 56 ispositioned in its right hand position (FIG. 2), the annular groove 6!)establishes communication between bypass passage 62 and return passage64 leading to a return pipe 66. Such urging may be effected by fluidpressure means in chamber 55 or by a manual or other control shown at 67as having schematic connection with the plunger extension 54.

A normally seated relief valve 68 may be provided to limit pressure inbypass passage 64. This valve is biased toward its seat 70 by a spring'72 and is positioned in the pump casing 12 such that when unseated oropen, communication is established between the return passage 64 and ayoke housing chamber 74 in the pump casing 12 by way of a passage 76, aspring chamber 78 and a passage 80. The chamber 74 is provided with areturn drain passage 82 leading to the intake passage 38 for recyclingthe fluid in the chamber 74.

A compensating device 84 is provided within a bore 86 in the pump casing12 to control the upper limit of the pressure of fluid discharge fromthe pump 14. The compensator device 84 comprises spool valve 88 havingan annular groove 90 located between opposite piston ends thereof. Theupper piston end 92 is subject to the fluid discharge pressure frompassage 44 and chamber 96 acting on the piston face 98 to tend to movethe spool valve 88 downward. The lower piston end 100 is subject to thefluid intake pressure from the intake passage 38, passage 102, passage104 and chamber 106 acting on the piston face 108 in cooperation withbiasing forces of a spring 110 to tend to move the spool valve upward toa normal position shown in FIG. 1. The spring 110 is positioned betweenthe piston face 108 and a bore 112 by an adjustable cap screw 114 in amanner that the spring biasing force acting on the piston face 108 canbe pre-regulated.

According to the positioning of the spool valve 88 (explainedhereinafter) two fluid pressure communications may be selectivelyestablished: a first communication shown in FIG. 1 includes chamber 55in the bore 52 adjacent the face of the spool valve 50, a passage 116 toa control opening below the lower face 118 of the upper piston end 92,the annular groove 90, a passage 120, and passage 102 to the intakepassage 38 such that the pressure throughout said communication ismaintained at the low level of intake fluid pressure. A secondcommunication shown in FIG. 2 includes the aforementioned chamber 55,passage 116 to a control opening above the upper face 98 of the upperpiston end 92 and passage 122 to the discharge passage 44 such that thepressure throughout said communication when established is at the levelof pump discharge fluid pressure when such pressure is high.

For simplicity of description it should be understood that all referencenumerals applied to FIG. 1 similarly can be applied to FIG. 2 and alsoFIG. 3 where applicable.

Referring to FIG. 3 there is shown a fluid circuit diagram including thefluid pump device 10 driven by the motor 18 for drawing fluid from areservoir 126 via a pipe 44 to the pump device 10 wherein said fluid ispressurized and delivered via a pipe 46 to any desired operating unit128 to perform a desired function and is returned via a main filter pipe130 including a large main filter 1132 and thence to the reservoir 126.A regulating valve 134 is provided in the pipe 46 to regulate the flowof fluid therethrough as desired. In the event of reduced rate of flowin the pipe 46 a bypass filter circult is provided from the pump device10, said circuit including pipe 66, and a pipe 136 to the reservoir 126.Said bypass filter circuit includes a cut-off valve 138 and a relativelysmall filter 140 in the pipe 136.

An alternate and preferred by-pass circuit is incorporated in FIG. 3 byclosing of valve 138 wherein the bypass flow from pump device 10 isdirected from pipe 66 via pipe 142 and open cut-off valve 144 into pipe130 thus eliminating the need for separate filter 140.

The flow path of the various pipes in the diagrams of FIG. 3 isindicated by arrows at various positions along the pipes. It should benoted that the terminology pipes" is utilized, wherein, tubing orsimilar conduit means may be included under the definition of pipes.

OPERATION Under normal operating conditions the pump 14 of the pumpdevice 10 is rotated by the motor 18 such that low pressure fluid iscirculated from the reservoir 126 through the pump 14, and delivered asfluid under pressure to the operating unit 128 to perform a controlfunction and thence returned to the reservoir 126. The reciprocatingaction of the pistons 26 within pump 14 causes the low pressure fluid tobe drawn from the intake passage 38 into the bores 22 and pumped out atthe discharge passage 44 as each bore passes said passages 38 and 44.The pistons 26 and bores 22 are manufactured with tolerancestherebetween that during the reciprocating action of the piston 26permits the leakage flow or a limited access flow of fluid between thewalls of the bores 22 and the pistons 26 into a fluid filled yokehousing chamber 74 such that the fluid in said chamber is beingcirculated from said chamber 74 via drain passage 82 to the low pressureintake passage 38 and thence either out the discharge 44 or recirculatedthrough the limited access flow between the piston 26 and bores 22 backto the yoke chamber 74. This circulation of leakage flow in addition tonormal circulation of incoming fluid from the low pressure reservoir tothe operating unit serves for both cooling and lubricating purposes forthe moving parts of the pump and associated ancillaries as long as thereis a relatively large amount of discharge of fluid from the pump. Whenthe fluid pressure requirements of the operating unit 128 have beenattained, or should the regulating valve 134 be operated to a reducedflow condition while the pump is still running at its operating rate ofspeed, the pressure to the operating unit 128 and in the dischargepassage 44 continues to increase slightly while the rate of flowtherethrough decreases. Under these conditions, the cooling andlubricating of the pump 14 and associated ancillaries becomes criticaldue to the reduced discharge rate efiecting reduced recirculation offluid. Also when the fluid pressure requirements of the operating unit128 have been attained, it is very often desirable to operate theassociated ancillaries such as driving motors, flowmeter or auxiliaryoperating units.

In the present invention there is provided by-pass flow control forsupplying fluid under pressure to a separate flow circuit for operating,lubricating or cooling associated ancillary equipment. The control offluid under pressure to this may be effected by manual operation of theaforementioned control device 67 to reposition the spool valve 50, orsuch repositioning can be accomplished automatically as now explained.When the discharge flow through pipe 46 is reduced by the decreasingdemands of operating unit 128, the flow of fluid through bypass 66 isautomatically increased. As the flow through pipe 46 is decreased, thepressure in passage 44 is increased. This increase in pressure is shownto be utilized to move spool valve 50 to the right in opposition to thebiasing force of spring 34 to un cover return passage 64. Movement ofspool valve 50 is affected by the build-up of pressure in dischargepassage 44 acting on the face of valve stem 54 in addition to the actionof compensating device 84 as now explained. Increase in pressure in thedischarge passage 44 and discharge pipe 46 transmitted via passage 122to chamber 96, acts on the piston face 98 of the spool valve 88 inopposition to the biasing force of the spring 110 to thereby repositionthe spool valve 88 downward as shown in FIG. 2. The spool valve 88 inits down position permits flow of the high pressure fluid from chamber96 past the upper piston end 92 to passage 116 and chamber 55 formed bythe bore 52 associated with spool valve 50. The high pressure fluid inchamber 55 causes the spool valve 50 to move toward its right handposition wherein the return passage 64 is completely uncovered to permitfull flow of fluid under pressure from the bypass passage 62 to returnpassage 64 and return pipe 66 to thereby further increase the intake oflow pressure fluid from the reservoir 126 through the pump 14 to thebypass passage 62 and thence to return passage 64 to be supplied toancillary equipment and back to reservoir 126. Simultaneously the valvestem 36 has positioned the yoke 30 to a position (shown in FIG. 2) withan angle of inclination approaching 90 degrees wherein the pump 14 isoperating with a pumping action sufficient only to maintain thisincreased bypass fluid circulation or operate ancillary equipment.

The pump continues to operate under this just described condition untilthe operating unit 128 begins to function, thereby creating a demand forfluid under pressure from discharge pipe 46. As the pressure in thedischarge pipe 46 and discharge passage 44 is reduced, the pressure inchamber 96 on top of the spool valve 88 of the compensating device 84 issimultaneously reduced. Reduction of pressure in chamber 96 permits thespring 110 to restore the spool valve 88 to its upper position (shown inFIG. 1) wherein the fluid under pressure in chamber 55 adjacent spoolvalve 50 is vented via passage 116, annular groove 90 and passage 120 tothe intake passage 38. With reduction of pressure in chamber 55, thespring 34 acts on the yoke flange 32 to tend to restore the yoke 30 andthe spool valve 50 to the position shown in FIG. 1 with normal pumpingoperation defined.

As described, the flow of fluid from return pipe 66 may be directed toeither the bypass filter circuit of pipe 136 or the bypass circuit ofpipe 142 as desired by proper operation of the cut-off valves 138 and144. If for any reason during operation, one or both of these circuitsbecome ineffective by filter clogging or undesired valve closing, theresultant pressure build-up in return pipe 66 and return passage 64would automatically open the relief valve 68 to permit continued fluidcirculation through the pump 14. It should be noted herein that if sodesired the bypass filter circuit of pipe 136 may be completelyeliminated to prevent difficulties resultant from the use of filter 140.

Although the flow control shown herein is shown and described asfunctioning with rotary barrel type pumps, it may readily be adaptedwith fluid circulation of other type pumps, without inventivemodification.

It should be noted herein that all directional references made hereinsuch as leftward", left hand, upward", etcetera, have been made relativeto the present drawings associated herewith and should not be construedas limiting requirements in actual applications.

Summarizing, there is disclosed herein a Pump Bypass Liquid Flow Controlwherein a pump operating with a high discharge flow rate may functionwith low or zero bypass flow rate, yet at low discharge flow rate willmodify its bypass flow rate in inverse relationship to the reduction indischarge flow rate. In addition, the pressure availability at thebypass discharge may be any required value from zero to full systempressure.

What is claimed is:

l. A pump assembly comprising: a pump casing; pump means operable withinsaid casing to pump fluid for flow between inlet and discharge sides ofsaid pump means; said pump means having a movable member which controlsthe quantity of fluid being discharged therefrom; a main dischargepassageway means communicable with the pump means discharge; a bypassdischarge passageway means selectively communicable with said pump meansdischarge; movable means to selectively control flow through said bypassdischarge passageway means and operable to establish such bypass flowwhen a predetermined pressure has been reached in said main dischargepassageway means; and said movable means additionally being operable toengage and move said movable member to decrease the quantity of fluidbeing discharged from said pump means when said predetermined pressurehas been reached.

2. A pump assembly as specified in claim 1 wherein said movable meansmaintains at least a cooling flow of fluid through said pump means.

3. A pump assembly as specified in claim 1 additionally includinganother movable means operable to establish communication between aportion of the flow through said main discharge passageway means andsaid first mentioned movable means when a predetermined pressure hasbeen reached in said main discharge passageway means.

4. A pump assembly as specified in claim 3 wherein such portion of suchflow through said main discharge passageway means aids said firstmentioned movable means in establishing such bypass flow.

5. A pump assembly as specified in claim 3 wherein said first and secondmentioned movable means are spring biased into a first position andestablishment of such a bypass flow requires overcoming such spring biasby the portion of the flow through said main discharge passageway means.

6. A pump assembly as specified in claim 1 wherein said movable means isspring biased into a first position and establishment of such a bypassflow requires overcoming such a spring bias.

l ll 4 t 4

1. A pump assembly comprising: a pump casing; pump means operable withinsaid casing to pump fluid for flow between inlet and discharge sides ofsaid pump means; said pump means having a movable member which controlsthe quantity of fluid being discharged therefrom; a main dischargepassageway means communicable with the pump means discharge; a bypassdischarge passageway means selectively communicable with said pump meansdischarge; movable means to selectively control flow through said bypassdischarge passageway means and operable to establish such bypass flowwhen a predetermined pressure has been reached in said main dischargepassageway means; and said movable means additionally being operable toengage and move said movable member to decrease the quantity of fluidbeing discharged from said pump means when said predetermined pressurehas been reached.
 2. A pump assembly as specified in claim 1 whereinsaid movable means maintains at least a cooling flow of fluid throughsaid pump means.
 3. A pump assembly as specified in claim 1 additionallyincluding another movable means operable to establish communicationbetween a portion of the flow through said main discharge passagewaymeans and said first mentioned movable means when a predeterminedpressure has been reached in said main discharge passageway means.
 4. Apump assembly as specified in claim 3 wherein such portion of such flowthrough said main discharge passageway means aids said first mentionedmovable means in establishing such bypass flow.
 5. A pump assembly asspecified in claim 3 wherein said first and second mentioned movablemeans are spring biased into a first position and establishment of sucha bypass flow requires overcoming such spring bias by the portion of theflow through said main discharge passageway means.
 6. A pump assembly asspecified in claim 1 wherein said movable means is spring biased into afirst position and establishment of such a bypass flow requiresovercoming such a spring bias.